Once the cheering died down and people stopped hugging and crying, Kerryn Phelps got to the stage at North Bondi Surf Lifesaving club to thank her “purple people”, her supporters in distinctive T-shirts who have spent the past three weeks promoting her campaign.

“What we have done is tapped into a sentiment in the Australian people, to talk about the issues that are important to them, not the issues about survival for a particular political party,” the newly minted independent member for Wentworth said.

“This win tonight should signal a return of decency, integrity and humanity to the Australian government,” she promised to wild cheers.

The emergence of the purple army and the fierce sentiments about the state of Australian mainstream politics should deeply worry the Liberal party. Labor too.

For many of Phelps’ campaigners, this was their first experience of political activism and they were energised by the experience.

Her supporters were friends, mothers who knew Phelps from their children’s school, people who were just deeply pissed off at the state of Australian politics.

One woman, who asked not to use her name, said she had voted Liberal all her life and had once been a member of the party. But when the former prime minister Malcolm Turnbull was dismissed and then the party preselected David Sharma, who had no connection with the seat, it was the last straw.

Carmen Caldwell, whose daughter had been to school with Phelps’ daughter, said it came down to integrity. “She demonstrates she does what she says she is going to do,” she said.

Others had been involved in the marriage equality campaign. Perhaps that had given them a taste for active democracy.

Chris Harris and Louis Carlivaro worked on the Potts Point booth.

“I have been very disappointed in the major parties, said Carlivaro. “I have voted Liberal in the past, but basically I am a Labor voter.”

Phelps did have some serious political operatives behind her: Darrin Barnett, who has worked at the Maritime Union of Australia, plus the heft of the Getup campaign crew and Stop Adani. That helped focus the campaign and give it boots on the ground.

But the bigger message is this: there are large numbers of people on the moderate side of politics who are deeply unhappy with the direction of the Coalition government and with the behaviour of both parties.

If political parties spend their entire time listening to the views of disengaged voters in marginal electorates in their focus groups, they run the risk of alienating the deeply engaged voters in what were once safe seats.

The Wentworth experience demonstrates those voters are both capable of voting strategically to make their views known and prepared to do it in large numbers.

Phelps’ slip of the tongue at the beginning of her speech when she thanked the people of Warringah – Tony Abbott’s seat – then quickly corrected herself, must have sent shivers down the spines of Liberal operatives.

Seats with educated populations who understand the preferential voting system will use it to send a clear message unless political parties respond to their concerns about climate change, the treatment of refugees, and representation of women in parliament.

Phelps issued a call to arms to other independents: “I would like to say to any young people, any women, any aspiring independents out there, if you are thinking of running for parliament or running for public office, yes, it can be tough, yes, the road can be hard, but it is so worthwhile that we have the right people stepping up to represent Australia.”

Down at the Intercontinental Hotel in Double Bay, in the large glitzy ballroom hired by the Liberals, the air of foreboding had settled even before Antony Green called it with just 10% of the vote counted.

Not that people at the Liberals party would have heard the news.

Their screens were on the Murdoch-owned Sky News, not the ABC.

Kerryn Phelps claims Wentworth byelection win for 'the people of Australia who need a voice' – live updates

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The prime minister, Scott Morrison, made a speech that was notable for the absence of congratulations to Phelps and its combative, divisive rhetoric that voters had just shown they rejected.

“My message to Bill Shorten is: you will never lead a country that you want to divide. For those who want to get ahead – small and family businesses – those who get up early in the morning, that’s the Liberal party. That’s who we stand for,” he said.

Thank heavens for the candidate Dave Sharma, who showed himself the gentleman he proved to be throughout the campaign. He graciously thanked not just Phelps, but also Labor’s Tim Murray and another independent, Licia Heath.

He said of Phelps: “She is a formidable citizen and whatever I can do to support her in her role, I will.”